Pushbutton reset circuit breaker having peripheral contact condition indicator means

ABSTRACT

An overload circuit breaker which has a main pushbutton which when depressed closes the circuit breaker and has a central cavity in its outer end, and a second pushbutton which, when both pushbuttons are depressed, is held arrested fully within the cavity and, when the main pushbutton is released, is likewise released and then projects for a certain distance out of the cavity and thus outwardly beyond the end surface of the main pushbutton. The end surfaces of both pushbuttons are preferably of the same color so that, when depressed, the second pushbutton will not be noticeable, but the peripheral surface of the second pushbutton is preferably of a different color contrasting with the color of the main pushbutton when the latter is in its outer off position and the second pushbutton projects from the main pushbutton.

[ PUSHBUTTON RESET CIRCUIT FOREIGN PATENTS OR APPLICATIONS BREAKER HAVING PERIPHERAL CONTACT CONDITION INDICATOR MEANS [7 1,073,615 Great'Britain........ Inventor; Jakob Ellenberger, Altdorf near I Nuernberg, Germany Primary Examiner-H. 0. Jones Attorney-George H. Spencer et al.

Assignee: Ellenberger &Poensgen GmbII, Altdorf near Nurnberg, Germany June 7,1972

[57] ABSTRACT An overload circuit breaker which has a main push- 22 Filed:

- button which when depressed closes the circuit [21 1 Appl' 260509 breaker and has a central cavity in its outer end, and a second pushbutton which, when both pushbuttons are Foreign Application Priority Data depressed,-is held arrested fully within the cavity and, when the main pushbutton is released, is likewise June 23, 197] Germany,.,...........,......9 71 24 044.3

released and then projects for a certain distance out of the cavity and thus outwardly beyond the end surface of the main pushbutton. The end surfaces of both pushbuttons are preferably of the same color so that, when depressed, the second pushbutton will not be noticeable, but the peripheral surface of the second 96 9 7l 7 v 79 3 311W ,0 7 R R3 U w .02 w on 2 "2/ R A 7 m2 6 mm 1 u .u 0 "u 0 n m I .C "h He HS C C .w UhF HUN 555 [ll pushbutton is preferably of a different color contrast- [56] Refere'lces cued ing with the color of the main pushbutton when the latter is in its outer off position and the second pushbutton projects from the main pushbutton.

UNITED STATESPATENTS 3 356,816 12/1967 Clarke.,......,............ ....337/79 X 3,629,763 12/1971 Walling et a], 7 Claims, 2 Drawing Figures PUSHBUTTON RESET CIRCUIT BREAKER HAVING PERIPHERAL CONTACT CONDITION INDICATOR MEANS The present invention relates to an overload circuit breaker which comprises a housing from which a pushbutton projects which when depressed closes the circuit breaker and is preferably also adapted for opening the circuit breaker. The outer end of this pushbutton has a recess or cavity in which a second pushbutton is located which is mounted on a rod which is slidable within the first pushbutton and is acted upon by a spring which, when the circuit breaker is switched off,

moves the second pushbutton out of the cavity in the first pushbutton for a distance which is predetermined by stops. When the circuit breaker is inits on position, the outer end surfaces of the first and second pushbuttons are substantially in plane alignment with each other. An overload circuit breaker of this construction is disclosed by the U.S. Pat. No. 2,633,515. In this circuit breaker, the rod which carries the second pushbutton has a lower end which forms a movable contact member and carries an angular bimetallic strip the free end of which engages under the action of the spring with the first pushbutton when the circuit breaker is in its on position. If an excessive current occurs, the bimetallic strip will bend so that its free end will disengage from the first pushbutton and the spring acting upon the second pushbutton will disengage the movable contact member on the lower end of the rod from the associated fixed contact and move the second pushbutton out of the cavity inthe first pushbutton. When this occurs, the first pushbutton remains in its depressed or .on position. The second pushbutton therefore only serves for indicating the trip-free release of the circuit breaker. The first pushbutton can only be moved by hand either to the on position or to the off position, and it will therefore not be moved to its off position if a normal thermally effected release of the circuit breaker occurs. f-

In some of the known overload circuit breakers in which, when the circuit breaker is released, the closing pushbutton moves to its off position in the direction outwardly of the housing, the peripheral surface of this pushbutton is provided with a sleeve which has a color different from that of the pushbutton itself. This sleeve is only visible when the circuit breaker is switched off and the pushbutton projects sufficiently from the housing. The fact that the circuit breaker is in its off position can therefore only be noticed by this projecting position of the pushbutton. If a larger number of such cir cuit breakers are mounted closely adjacent to each other and the light conditions are also poor, for example, in airplanes, it is often very difficult to notice quickly and reliably which ofthe many circuit breakers might be switched off or released.

It is an object of the present invention to provide an overload circuit breaker of the type as previously described which is designed in such a manner that, when the circuit breaker is in its off position, the second pushbutton projects from the main closing pushbutton and the latter then also projects further from the housing of the circuit breaker than it does when it is in its on position.

For attaining this object, the invention provides the housing of the circuit breaker with a fixed stop which engages into or traverses a bore in the main'pushbutton and on which, when the circuit breaker is in its on position, a resilient holding projection on the rod carrying the second pushbutton is arrested so as to maintain the upper surfaces of both pushbuttons in alignment with each other.

When the overload circuit breaker according to the invention is switched off which may be effected either by electromagnetically or thermally controlled means or by hand, the main or closing pushbutton is moved by a release spring or by hand to its off position in the direction out of the housing. During this movement, the main pushbutton takes along the second pushbutton, and the holding projection on the rod carrying the second pushbutton then yields resiliently and disengages from the fixed stop on the housing. The spring which acts upon the second pushbutton then presses the latter out of the cavity or recess in the end of the main pushbutton. The person supervising the circuit breaker will then recognize that the latter is switched off not only by the projecting off-position of the main pushbutton, but especially also by the appearance of the second pushbutton which then projects from the main pushbutton.

Another feature of the invention consists in the provision of suitable guide means for insuring that, when the rod carrying the second pushbutton is released during the outward movement of the first pushbutton to its off position, this rod will slide freely in its axial direction within the first pushbutton until the second pushbutton is arrested in a position in which it projects for a certain distance from the cavity in the end of the first pushbutton.

Another feature of the invention consists in the provision of suitable resilient means for arresting the second pushbutton in its depressed position within the cavity, that is, when both pushbuttons have been depressed and the first pushbutton is in its on position.

Another feature of the invention consists in rendering the second pushbutton when projecting from the outer end of the first pushbutton more clearly noticeable. For this purpose the invention provides the peripheral surface of the second pushbutton to be made of a colored plastic contrasting with the color of the first pushbutton. It is of still greater advantage, especially if one or a series of circuit breakers according to the invention are mounted in a place where the pushbuttons are very poorly lit by outside illumination, to make the second pushbutton of each circuit breaker, preferably with the exception of its outer end surface, of a fluorescent plastic. The outer end surface of the second pushbutton is preferably made of the same color as the first pushbutton so that, when both pushbuttons are in their depressed position and the circuit breaker is therefore in its closed position, an observer of the circuit breaker, overlooking that the second pushbutton projects from the first, may not be misled to believe that the circuit breaker is switched off. If desired, the outer end surface of the second pushbutton may also be provided with a marking, for example, of the circuit which this circuit breaker controls or of the amperage for which it is intended.

In addition, the first or main pushbutton may also be provided with a sleeve which has a different color than the pushbutton itself and becomes visible only when this pushbutton is in its off position.

The features and advantages of the present invention will become more clearly apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings, in which FIG. 1 is a side view of an overload circuit breaker according to the invention in its off position in which, however, the upper part of its housing is broken away and the two pushbuttons and their adjacent parts are shown in cross section; while FIG. 2 is a similar view of the same circuit breaker, but in its on position.

As illustrated in the drawings, the overload circuit breaker according to the invention comprises a housing 1 in which a mounting sleeve 2 is secured the outwardly projecting part of which has an outer screw thread for mounting the circuit breaker on a switchboard, dashboard or the like. Along the inner wall of this sleeve 2 a first or closing pushbutton 3 is slidable the upper end of which is enlarged by an annular outwardly projecting flange 4 which permits this pushbutton to be more easily depressed to its on position and also permits the pushbutton to be pulled out to its off position. On its outer peripheral surface, but spaced from its upper end, pushbutton 3 carries a thin cylindrical sleeve 5 which has a color different from that of the pushbutton 3 itself. When the circuit breaker is in its on position, as shown in FIG. 2, this sleeve 5 is not visible, but when the circuit breaker is in its off position as shown in FIG. 1, sleeve 5 will project out of the mounting sleeve 2 and this off position will thus be easily noticeable.

The upper end part of pushbutton 3 is provided with a central cavity or recess 6 in which a second pushbutton 7 is axially slidable. This second pushbutton 7 is secured to a short rod 8 which is slidable within a bore 9 in the main pushbutton 3. A compression coil spring 10 around the rod 8 presses with its lower end upon the bottom shoulder of the recess 6 and with its upper end upon the second pushbutton 7 and thus tends to shift the latter upwardly so as to project from the upper surfaceof' the main pushbutton 3 and its flange 4. Thelower part of the rod 8 is divided by an elongated hole 11 and a narrow slot 12 at the lower end of this'hole into two resilient arms 13 the lower ends of which are provided with two inner and outer holding projections 14 and 16. When the circuit breaker is in its on position as shown in FIG. 2, the inner holding projections 14 are hooked over and held by a stop pin 15 which is secured to the housing 1 and located within the main pushbutton 3, while when the circuit breaker is in its off position as shown in FIG. 1, the outer projections 16 on the two resilient arms 13 form stop shoulders which under the action of spring 10 abut against an annular shoulder 17 in the main pushbutton 3. The elongated hole 1 1 has a width substantially equal to the thickness of the pin 15.

The second pushbutton 7 consists of a colored or fluorescent plastic so that, when it projects from the main pushbutton 3, its outer peripheral surface contrasts with the different color of the latter and may be clearly seen. However, the upper end surface 18 of pushbutton 7 has the same color as the main pushbutton 3 so that, when pushbutton 7 is depressed and held within the recess 6 in the main pushbutton 3, no color differences will be noticeable on pushbutton 3. The end surface 18 of pushbutton 7 may also be provided with a marking, for example, of the amperage for which the circuit breaker is intended or of the particular circuit which it controls.

When the circuit breaker is in its on position as shown in FIG. 2 and it is then released either by thermally or electromagnetically controlled means or by hand, the main pushbutton 3 will be moved to its off position as shown in FIG. 1 either by a release spring or by being pulled by hand. During this movement of the main pushbutton 3, it will take along the other pushbutton 7 with its rod-shaped extension 8, and the two resilient arms 13 of this rod 8 will thereby flex outwardly so that their inner projections 14 can slide upwardly over the stop pin 15 which is secured to the housing 1. After the rod 8 has disengaged from the stop pin 15, pushbutton 7 is pushed by spring 10 to its off position as shown in FIG. 1. This off position may be clearly seen by the appearance of the colored sleeve 5 on pushbutton 3 and especially also by the second pushbutton 7 which then projects from the main button 3. Since the main button 3, the sleeve 5 and the second button 7 all differ in color from each other, a person looking at the circuit breaker cannot help but notice its off position.

the latter will spread the two arms 13 slightly apart and I thereby widen the slot 12 so that the stop pin 15 can pass through the slot until the inner holding projections 14 snap over the stop pin. The circuit breaker is then again in its on position as shown in FIG. 2.

The circuit breaker according to the invention may also be designed so as to effect a trip-free release when both pushbuttons are in the depressed position as shown in FIG. 2. y v Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

Having thus fully desclosed my invention, what I claim is:

1. An overload circuit breaker having a housing, a first main pushbutton axially slidable within said housing and having an outer end projecting from said housing and adapted to be pressed from an off position toward and more deeply into said housing to its on position in which said circuit breaker is closed, said first pushbutton having a cavity in its outer end, a rod axially slidable along said first pushbutton and having an enlarged outer end forming a second pushbutton adapted when depressed to be located substantially fully within said cavity so that when bothof said pushbuttons are depressed and said first pushbutton .is thereby moved to its on position, the outer ends of said two pushbuttons will be substantially at the same level, spring means acting upon said second pushbutton and tending to press said second pushbutton out of said cavity, a stop member rigidly secured to said housing, a resilient member on said second pushbutton resiliently said two pushbuttons for limiting the distance to which said second pushbutton when moving to its released position under the action of said spring may project from said cavity and beyond said outer end of said first pushbutton.

2. An overload circuit breaker as defined in claim 1, in which the other end of said rod of said second pushbutton is radially resilient by being provided with an axially extending slot which divides said other end part into two resilient arms, the longer upper part of said slot having a width substantially equal to the thickness of said stop member forming a pin secured to said housing and extending transversely to said slot, and the lower end of said slot adjacent to the free ends of said arms being narrower than the thickness of said pin so that shoulders are formed between the wider and narrower slot parts, said pin being adapted resiliently to expand said narrower slot part and then to enter said wider slot part when by the pressure of a finger said second pushbutton is first depressed into said cavity and said first pushbutton is then depressed to its on position, whereupon when said finger pressure is then released, the outward movement of said rod and said I secondpushbutton under the action of said spring will be arrested by said shoulders hooking over said pin and said outer end surfaces of said two pushbuttons will then be held at substantially the same level.

3. An overload circuit breaker as defined in claim 2,

in which said associated means for limiting the outward movement of said second pushbutton from said cavity comprises a radially outward projection on at least one of said arms near its free end and an associated projection on said first pushbutton, said projections when engaging upon each other under the action of said spring limiting the length to which said second pushbutton may projectfrom said first pushbutton when the latter is in its off position.

4. An overload circuit breaker as defined in claim 1, in which said secondpushbutton has a peripheral surface part of a color different from the color of the visible parts of said first pushbutton.

5. An overload circuit breaker as defined in claim 4, in which at least said peripheral surface part of said second pushbutton consists of a fluorescent plastic.

6. An overload circuit breaker as defined in claim 4, in which the outer end surfaces of said two pushbuttons have the same color.

7. An overload circuit breaker as defined in claim 1, further comprising a sleeve surrounding and secured to a part of said first pushbutton which is invisible when said first pushbutton is depressed to its on position and visible when said first pushbutton is in its off position, said sleeve having a color different from the color of said second pushbutton. 

1. An overload circuit breaker having a housing, a first main pushbutton axially slidable within said housing and having an outer end projecting from said housing and adapted to be pressed from an off position toward and more deeply into said housing to its on position in which said circuit breaker is closed, said first pushbutton having a cavity in its outer end, a rod axially slidable along said first pushbutton and having an enlarged outer end forming a second pushbutton adapted when depressed to be located substantially fully within said cavity so that when both of said pushbuttons are depressed and said first pushbutton is thereby moved to its on position, the outer ends of said two pushbuttons will be substantially at the same level, spring means acting upon said second pushbutton and tending to press said second pushbutton out of said cavity, a stop member rigidly secured to said housing, a resilient member on said second pushbutton resiliently interengaging with said stop member when both of said pushbuttons are depressed for holding said second pushbutton in its depressed position within said cavity, said first pushbutton when moving to its off position adapted to take along said second pushbutton and its rod and thereby disengaging said resilient member from said stop member, and associated stop means on said two pushbuttons for limiting the distance to which said second pushbutton when moving to its released position under the action of said spring may project from said cavity and beyond said outer end of said first pushbutton.
 2. An overload circuit breaker as defined in claim 1, in which the other end of said rod of said second pushbutton is radially resilient by being provided with an axially extending slot which divides said other end part into two resilient arms, the longer upper part of said slot having a width substantially equal to the thickness of said stop member forming a pin secured to said housing and extending transVersely to said slot, and the lower end of said slot adjacent to the free ends of said arms being narrower than the thickness of said pin so that shoulders are formed between the wider and narrower slot parts, said pin being adapted resiliently to expand said narrower slot part and then to enter said wider slot part when by the pressure of a finger said second pushbutton is first depressed into said cavity and said first pushbutton is then depressed to its on position, whereupon when said finger pressure is then released, the outward movement of said rod and said second pushbutton under the action of said spring will be arrested by said shoulders hooking over said pin and said outer end surfaces of said two pushbuttons will then be held at substantially the same level.
 3. An overload circuit breaker as defined in claim 2, in which said associated means for limiting the outward movement of said second pushbutton from said cavity comprise a radially outward projection on at least one of said arms near its free end and an associated projection on said first pushbutton, said projections when engaging upon each other under the action of said spring limiting the length to which said second pushbutton may project from said first pushbutton when the latter is in its off position.
 4. An overload circuit breaker as defined in claim 1, in which said second pushbutton has a peripheral surface part of a color different from the color of the visible parts of said first pushbutton.
 5. An overload circuit breaker as defined in claim 4, in which at least said peripheral surface part of said second pushbutton consists of a fluorescent plastic.
 6. An overload circuit breaker as defined in claim 4, in which the outer end surfaces of said two pushbuttons have the same color.
 7. An overload circuit breaker as defined in claim 1, further comprising a sleeve surrounding and secured to a part of said first pushbutton which is invisible when said first pushbutton is depressed to its on position and visible when said first pushbutton is in its off position, said sleeve having a color different from the color of said second pushbutton. 